Play games
Choose the game that interests you and play itfor free.
Complete the quests
Every game has some quests for which you will receive Soul Gems.
Receive rewards
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
... in the sense that they are soooo misleading when compared to the main game. The animated ads make the game look amazing when really, it's not the best in my opinion.